Cassidy, a lesbian who helped spearhead the legalization of same-sex marriage in Illinois, told her colleagues people are born heterosexual, homosexual or bisexual, and so-called “conversion therapy” can only harm the youths it purports to treat.

“The experts have weighed in. This is codifying the positions of every major mental health profession’s organization. This gives the Department of Professional Regulation the tools they need to protect the victims that I have heard from who have been horribly, horribly humiliated and abused,” Cassidy said.

She said, in her own case, an understanding priest helped preserve her relationship with her mother when Cassidy came out as a lesbian.

Though 51 members of the house voted against the proposal, only Rep. Jeanne Ives (R-Wheaton)

“This is stuff that we should not be legislating on at all. We have no purview in this department. We have no expertise in this department. It’s absolutely something that should not ever be legislated on. Let people decide for themselves what they need to have for themselves,” Ives said.

Cassidy said mental health experts have weighed in, and have said there’s no scientific basis for treating a person’s sexual orientation as a mental illness or disorder. She said it can cause depression and lead to suicidal actions.

Had the measure passed, mental health practitioners would have been barred from treating homosexuality or bisexuality as a disease, and licensed therapists who performed conversion therapy would have been sanctioned for unprofessional conduct.

Twenty members of the House were absent for the vote. Sixteen more yes votes were needed for passage.